1. Field of the Invention
This invention relates in general to automated sensing of an object or a characteristic of that object in or derived from an image of a scene and more particularly, to both a method and apparatus for sensing of target data associated with an object in a scene generated on an image by an integrated circuit at a focal plane of an imager and which allows rapid processing in parallel and with substantially improved ability to filter objects of interest or characteristics of that object of interest.
2. Brief Description of Related Art
Compact systems which employ image sensors for generating and recording images in an electronic device have proliferated rapidly in past several years. Personal data devices and even miniature computers are frequently carried by individuals and which devices have the capability of generating images along with generation of data, or perform other activities for which they are designed to accomplish. Cell phones, digital cameras and camcorders are some examples of these commercially available consumer and/or military products which have image sensing capabilities.
The small size and the requirement for portability allow products of this type to benefit from the existence of the recent improvements in miniature electronics. Moreover, these improvements allow for size reduction and weight reduction, as well as a reduction in power consumption of the image sensing apparatus. However, image sensing is almost necessarily performed with a circuit different from that circuitry used for processing the image. Image sensing in the same integrated circuit chip would allow for the benefit of imagers with increased performance and dim object sensitivity, as well as in an increase in detection range, and user convenience and utility.
In the past decade, image sensing using digitally controlled image sensors has improved substantially with improvements in integrated circuits and various processing techniques. Accurate detection of an activity which may take place at a remote site is highly desirable when the detection generates an accurate image of a scene and an object in that scene with good visibility and accuracy and would effectively find use in numerous military applications and in crime solving and the like. As a simple example, by quickly analyzing an image it is possible to detect a source of an object or a characteristic of that object and where the source of that object or characteristic may be, for example, a launcher of a projectile. By knowing the location of the source at that remote site, it is possible to take offensive action against such activities, such as destroying the source of that projectile.
One of the primary problems in detection of target data within an image and generated by an integrated circuit is that background clutter and images of other objects or characteristics of these other objects appear in a scene. Again, as a simple example, if one was trying to determine the source of a projectile, and an automobile was moving in proximity to the site of the projectile source, a processing apparatus and method would generate images from those automobile signals, thereby interfering with the detection of the projectile or a characteristic, such as a trajectory, and hence location of a source of the projectile.
In recent years, there have been a number of visible and infrared based sensors that create images from semi-conductor materials rather than from a film. These sensors typically operate at the focal plane with analog, or otherwise, digital electronics and in all cases are external to and may be quite remote to a detector and a read-out integrated circuit. At present, the read-out integrated circuit is used to sense the photo-current which is generated from a silicon or other semiconductor material while transforming the signals, such as the photo-currents into images.
There have been attempts to add more functionality to the read-out integrated circuit including for example, arbitrary window addressing and high speed multiplexing. The present invention, in contrast, provides a much greater improvement in the development of read-out integrated circuit processing by the use of fully parallel analog processing techniques. These analog processing techniques make the use of the high density circuitry now available. Some of these circuits allow for detecting over one hundred objects of interest in the pixel regions of the image read-out integrated circuit.
In the past, only a limited amount of image processing could have been performed at the focal plane array of sensors. However, processing was limited and the problem of excess noise was typically quite large in the prior art devices. The downstream noise in a signal path oftentimes materially interfered in the attempts to determine an activity at an image scene. Moreover, digital signal processing designers avoided focal plan array processing because of the significantly high cost involved.
In addition to the foregoing, in the prior art image sensors, battery life was relatively short due to the amount power required for any efficient operation of the image sensor and processor. Moreover, weight was also another factor, particularly where the image sensor and support electronics had to be transported manually. Often times, the size of the image sensor equipment substantially reduced its functionality. In fact, because of stringent weight and size and cost limitations and the fact that practically all imaging systems required external processing, image sensor technology is still avoided in many areas where it could be used. Furthermore, these systems were not sufficiently light in weight and small and compact so that they could be transported in a field environment.
It would be desirable to provide a device capable of sensing an image and reproducing that image on a display while using a single chip containing both sensor and a processing algorithm for data on the same circuit chip and without reliance upon an external processor, such as a desk-top digital computer for digital signal processing into an image. In the preferred embodiment of the invention it is even preferable that the sensor and the associated electronic processor has the capability of sensing and reading out multiple high resolution fovea and to start and stop fovea based on the existence of a signal of an object in an image without an external processor. A device of this type must necessarily be user friendly and provide a variety of working modes simultaneously.